How to draw the line with sharp ends /gradient line/ in flutter?

Question

Using stroke method, how to create gradient line with sharp end in flutter? I want to draw the line as below in flutter.

Answer 1

Use CustomPainter to draw:

import 'package:flutter/material.dart';

void main() => runApp(Example());

class Example extends StatefulWidget {
  @override
  _ExampleState createState() => _ExampleState();
}

class _ExampleState extends State<Example> {
  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: Scaffold(
            body: Center(
      child: CustomPaint(
        size: Size(200, 5),
        painter: CurvePainter(),
      ),
    )));
  }

  @override
  void dispose() {
    super.dispose();
  }
}

class CurvePainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    var paint = Paint();
    paint.color = Colors.black;
    paint.style = PaintingStyle.fill; // Change this to fill

    var path = Path();

    path.moveTo(0, 0);
    path.quadraticBezierTo(size.width / 2, size.height / 2, size.width, 0);
    path.quadraticBezierTo(size.width / 2, -size.height / 2, 0, 0);

    canvas.drawPath(path, paint);
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return true;
  }
}

Answer 2

modified sleepingkit answer:

import 'package:flutter/material.dart';

class PointedLinePainter extends CustomPainter {
  final double width;

  PointedLinePainter(this.width);

  @override
  void paint(Canvas canvas, Size size) {
    var paint = Paint();
    paint.color = Colors.white;
    paint.style = PaintingStyle.fill;

    var path = Path();

    path.moveTo(0, 0);
    path.quadraticBezierTo(width / 3, 0.5, width, 0);
    path.quadraticBezierTo(width / 3, -0.5, 0, 0);

    canvas.drawPath(path, paint);
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return true;
  }
}

somewhere in code:

Container(
      margin: EdgeInsets.symmetric(horizontal: 10.0),
      alignment: Alignment.centerLeft,
      width: MediaQuery.of(context).size.width,
      height: 2,
      child: CustomPaint(
        painter:
            PointedLinePainter(width - 2 * horizontalPointedLineMargin),
      ),
    )